In casting aluminum base alloys directly into sheet form by various methods, including that carried out in the Hunter caster (see U.S. Pat. No. 2,790,216), it has been common to experience edge cracking of the sheet as it issues from the caster. The cracks in the edges extend into the sheet and are of a character such that during ensuing cold reduction of the sheet, the cracks propagate inwardly. As a result, it has been considered necessary to edge shear continuously cast sheet aluminum based alloys of the 3105 Aluminum Association classification and others. This means that the scrap sheared off the edges of the sheet represents wasted energy consumed in melting the aluminum alloy going into the scrap. Additionally the cost of the edge shearing operation plus the recycling of the scrap both involve additional expense.
Applicants have sought to eliminate edge cracking in aluminum based alloys, such as the Aluminum Association 3105 alloy and the new 3007 alloy, without deleteriously affecting the physical properties, the shape and the surface of the final cold reduced product. The applicants have accomplished this desideratum by merely increasing or decreasing certain alloying constituents while correspondingly decreasing or increasing others.